Fire damage to the engine indication electrical harness and interface disrupted the electrical system and resulted in the illumination of the master warning caution light, chip detector light, and caused the oil pressure indication to drop to zero. The soot found on the shoulders of the12,10 and 8o'clock hold-down nut receptacles on the attach flange of the starter/generator indicates that these three hold-down nuts were not fastened during the fire. Without these hold-down nuts being properly tightened, there would be insufficient clamping force holding the starter/generator in place, and it would vibrate. The vibration chafed a hole through the fuel line, allowing fuel to dribble past the cooling fan cap of the starter/generator and onto the commutator. It is likely that heat generated by the starter/generator and sparks emitted by the commutator and brushes acted as an ignition source, resulting in a fire. With power on, the engine produced fuel pressure in the chafed fuel line that kept feeding the fire. It was not determined how the fuel line became trapped between the top of the starter/generator and the diffuser housing. It was considered likely that the vibration of the starter generator also induced the cooling fan cap screws to back out. After the cap separated, it was retained over the cooling fan blades by the pinched fuel line, resulting in abrasion of the cooling fan. The abrasion of the cooling fan did not contribute to the failure of the fuel line. The fire bottle was discharged during the descent with engine power on. It is considered likely that the fire was momentarily suppressed, but because of the constant supply of fuel and ignition, it re-ignited after the retardant was spent. The following TSB Engineering Lab Report was completed: LP 104/02 - Starter/generator and Fuel Hose Analysis.Analysis Fire damage to the engine indication electrical harness and interface disrupted the electrical system and resulted in the illumination of the master warning caution light, chip detector light, and caused the oil pressure indication to drop to zero. The soot found on the shoulders of the12,10 and 8o'clock hold-down nut receptacles on the attach flange of the starter/generator indicates that these three hold-down nuts were not fastened during the fire. Without these hold-down nuts being properly tightened, there would be insufficient clamping force holding the starter/generator in place, and it would vibrate. The vibration chafed a hole through the fuel line, allowing fuel to dribble past the cooling fan cap of the starter/generator and onto the commutator. It is likely that heat generated by the starter/generator and sparks emitted by the commutator and brushes acted as an ignition source, resulting in a fire. With power on, the engine produced fuel pressure in the chafed fuel line that kept feeding the fire. It was not determined how the fuel line became trapped between the top of the starter/generator and the diffuser housing. It was considered likely that the vibration of the starter generator also induced the cooling fan cap screws to back out. After the cap separated, it was retained over the cooling fan blades by the pinched fuel line, resulting in abrasion of the cooling fan. The abrasion of the cooling fan did not contribute to the failure of the fuel line. The fire bottle was discharged during the descent with engine power on. It is considered likely that the fire was momentarily suppressed, but because of the constant supply of fuel and ignition, it re-ignited after the retardant was spent. The following TSB Engineering Lab Report was completed: LP 104/02 - Starter/generator and Fuel Hose Analysis. The fuel line to the VIGVA was pinched between the top of the starter/generator cooling fan housing and the diffuser housing. Three starter/generator hold-down nuts at the12,10 and 8o'clock positions were not fastened, allowing the starter/generator to vibrate. Because the fuel line was pinched against the vibrating starter/generator, it chafed through, allowing fuel to enter the starter/generator, which resulted in an engine fire.Findings as to Causes and Contributing Factors The fuel line to the VIGVA was pinched between the top of the starter/generator cooling fan housing and the diffuser housing. Three starter/generator hold-down nuts at the12,10 and 8o'clock positions were not fastened, allowing the starter/generator to vibrate. Because the fuel line was pinched against the vibrating starter/generator, it chafed through, allowing fuel to enter the starter/generator, which resulted in an engine fire. The hold-down nut at the 12o'clock position was left off for ease of starter/generator removal and installation.Findings as to Risk The hold-down nut at the 12o'clock position was left off for ease of starter/generator removal and installation. The vibration of the starter/generator induced the separation of the cooling fan cap, resulting in the abrasion of the cooling fan blades.Other Findings The vibration of the starter/generator induced the separation of the cooling fan cap, resulting in the abrasion of the cooling fan blades. Transport Canada is conducting a review of the applicable Bell205A-1 instructions for continuing airworthiness to determine if action is necessary regarding the instructions for the installation of starter/generators and fuel lines.Safety Action Transport Canada is conducting a review of the applicable Bell205A-1 instructions for continuing airworthiness to determine if action is necessary regarding the instructions for the installation of starter/generators and fuel lines.